1. Field of the Invention
This invention relates generally to a machine for producing extruded products, and more particularly to a machine for producing polymers that are cross-linked by adding at least one additive in a polymerization reaction.
2. Description of the Related Art
Machines for producing cross-linked extruded products are known, for example, from German patent 2,554,525, where it is designed as a screw extruder into which the polymer is fed through a feed hopper. The other ingredients that must be added to the polymer are usually injected in liquid form into the lower portion of the feed hopper or directly into the neck part of the extruder of this type of machine.
For complete and uniform cross-linking of polymers, it is crucial for adequate mixing of all ingredients to be achieved. However, this is precisely one of the main disadvantages of the known type of equipment. By merely injecting certain ingredients into the polymer, which is in the extruder feed hopper or in the neck of the extruder, a high additive concentration is achieved only in the area around the injection site. The reaction mixture must then be blended again during homogenization by means of an extruder worm gear with a complicated design as part of the extruder. In addition to the resulting unfavorable conditions for good cross-linking, this requires an extruder with a complex design that can be manufactured only at great expense.